Bit of a CF at the dyno as the previous tune was a 1bar SD tube and we are switching to MAF based tuning. Unfortunately we were getting no MAF signal, after investigation it turns out I had forgotten to reconnect the MAF wires in the harness which were disconnected for the original SD tune. Of course in GM's wisdom the MAF connector wires are all white! And the custom harness from PSI did not use the factory colors so reconnection was a biotch as I didnt have my notes with me. In the end we decided to stick with SD for the afternoon, but the HP tuners would not apply the upgrade from 1 bar to 3 bar SD, so we were flying blind with no control above 100KPA MAP. No biggie as this was just initial testing.

However at the end of the afternoon something happened and it threw the serpentine belt which in turn tore off the two custom idler pulley and made a mess. So winch on the trailer and back to the shop for repairs and updates. Back to the dyno next week for the base tune. Then some miles, then back again for boost tune.

Just for grins and giggles we did a partial 3/4 throttle pull from 2K to about 4K and overlayed the curves on last years final SD stock LS1 tune. As you can see the curves point to a significant potential

This was 5psi, and there was basically zero lag.

Bumper is back from paint and looks great, should have it back to street ready next week.

Sorry all, I'll be a no show at Carlisle :( things have conspired against me this week and I just can't make it. Judas has an allergic reaction to its serpentine belt which hopefully I can resolve this weekend.

I was seeing oil out of one tailpipe and my custom sight glass on that turbo drain was full. That turbo was leaking oil past it's seals. Ordered a pair of t3 rebuild kits with upgraded thrust bearings and seals, again from eBay for $30 a kit. Interested to see what the bearings etc look like.

What are you using for a sump pump to get the oil back to the oil pan? It is extremely hard to blow out seals on a turbocharger, and usually if they are leaking, it is because they are not getting proper evacuation of oil or have improper oil restriction.

Today I pulled the turbos for review and install of the turbo bearing kit with upgraded bearings and seals.

When I pulled the passenger side turbo about a quart of oil came out of the hot side, so the seals were toast for sure.

I was interested to see how these eBay turbos looked inside and overall they were not bad. The seals and shaft seal rings were certainly sub par quality compared to the parts in the rebuild kit.

Both turbos are rebuilt and back in now. I did a leak vacuum leak test and they are way better. The pump will pull about .5" vac without the motor running.u have to wait overnight for the gasket sealant in the drain to cure. Tomorrow I will put the radiator etc back in and fire it up and see how the pump scavenged the turbos. If all is good ill take it for a road test for the new serpentine belt setup, and hopefully all will be good so I can button it all up to get it roadworthy.